Burner ignition and flame detection means



Aug. 26, 1952 CLARK 2,608,245

BURNER IGNITION AND FLAME DETECTION MEANS Filed March 27, 1950 VII/5.

INVENTOR /2 f'fllA/A/PO R CLARK.

A TIER/Vi) Patented Aug. 26, 1952 BURNER IGNITION AND FLAME DETECTION I MEANS Edward R. Clark, Baldwin, N. Y., assignor to Peabody Engineering Corporation, New York, N. Y., a corporation of New York Application March 27, 1950, Serial No. 152,215

3 Claims.

This invention relates to igniters for fuel burners and more particularly to a combination igniter and flame detector which may be applied as a unit to a gas, pulverized fuel, or oil burner.

An object of the invention is to provide an ignition unit of the above type which requires only a single aperture in the burner throat.

Another object is to provide an ignition unit offering minimum interruption of the continuity of the burner throat and minimum disturbance in the flow of combustion air therethrough.

Another object is to provide dual ignition burners with a flame detector to prevent the flow of fuel to the main burner unless one of the ignition burners is lighted and with a flame detector to shut down the main burner fuel supply in event of flame failure.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

The invention is applicable to igniter systems having timing means to supply gas to the ignition burners and energize the igniters for a predetermined period, supply fuel to the main burner after the ignition burners have produced a flame and shut down the main burner after the ignition burners have been shut off unless a flame detector detects the presence of a flame from the main burner.

The present system provides a pair of ignition burners, each with its own flame detector rod and igniter and a flame detector for the main burner arranged in a unit. The ignition burner flame detector rods may be so connected that the main fuel valve is opened only if one of the ignition burners has been lighted or if desired may be connected to require lighting of both ignition burners before the main fuel valve is opened. The flame detector for the main burner becomes effective after the ignition burners have ceased operating and hence the latter cannot influence this flame detector. In the case of an oil or pulverized fuel burner a photo-electric flame detector may be used. In the case of a gas burner, the flame is non-luminous and a flame detector rod may be used. Only one ignition burner may be used if desired.

The nature of the invention and its mode of operation Will be better understood from the following description and the accompanying drawings in which a specific embodiment has been set forth for purposes of illustration.

In the drawings:

Fig. 1 is a longitudinal vertical section through a burner embodying the present invention;

Fig. 2 is an enlarged sectional view through the igniter unit taken on the line 2-2 of Fig. 1; and

Fig. 3 is a sectional view on line 33 of Fig. l on a reduced scale.

Referring to the drawings morein detail, the invention is shown asapplied to a burner havin a fuel admission barrel |ll provided with .a burner tip firing through a burner throat I2 in a refractory wall |3 of a furnace. Air for combustion is supplied from a duct, l4 to a burner tube I5 surrounding the barrel ID. The barrel I0 is supplied with pulverized fuel,. oil or gas, through a fuel pipe Hi. The burner is of standard construction and only so much thereof has been shown .as is necessary to an understanding of the present invention. v

The igniter unit comprises a fan-shaped housing having a plurality of separate tubes 2|, 22, 23, angularly disposed in the same plane and registering with a common opening 24 in the housing 20. The tubes 2| and 23 contain ignition burners and ignitersto vbe described. The tube 22 contains a flame detector 26 which, may have a flame detector rod projecting through the opening 24 into the path of the main gas burner flame. In the case of an oil or pulverized fuel burner, the rod .25 may be replaced by other standard flame detectors of known. form.

The housing 20 also contains a pair of intermediate tubes 30 and 3|. disposed adjacent the tubes 2| and 23 and carrying flame detector rods 32 and 33 which project into the path of the ignition burner flames from the tubes 2| and 23 respectively. The flame detector rods 25, 32 and 33 are suitably insulated from the housing 20 and r are connected to close a circuit through the flame when the respective burners are operating.

Each ignition burner comprises a gas tube 4!! extending through a head 4| in the tubes 2| and 23 and terminating in a tip 42 having a gas inlet 49, central gas opening 43 and a cup 44 forming an ignition chamber. Air is supplied to the housing 20 through ports 45 and passes around the tube 40 to mix with the gas fuel at the end of the cup 44. A portion of this air passes into the cup 44 through ports 46 therein. The electric igniter comprises an electrode 41 extending through an insulator 48 in each of the tubes 40 and through the opening 43.

The unit is supplied with fuel gas from a timed control and with air from a suitable source which may be the source of air to the burner.

The housing 20 is disposed adjacent the burner with the opening 24 registering with an opening 50 in the burner throat I 2.

Operation The above described unit may be connected to the burner control to operate in a timed cycle. First gas is supplied to the two ignition burner tubes 40 and simultaneously the ignition elec trodes 41 are energized. The two ignition burners normally ignite and the gas flame therefrom passes through the opening 24- to the burner throat. At the same time the flames play on rods 32 and 33 and close a control circuit to the main fuel valve. The connections may be such that energization of eitheror both ignition burner flame detector rods is necessary to openthe fuel valve to the main burner. The flame detector rods thus prevent the introduction of fuel into the furnace from the main burner unless one or both of the ignition burners is lighted, depending upon the connection.

Normally the .main burner fuel valve opens and after a predetermined period the ignition burners cease operating. Thereafter the flame detector rod 25 must indicate a flame from the main burner or the main fuel valve again closes.

The system is simple and compact and may be applied as .a unit to .a burner, requiring only one opening to .the burner .throat. It may also be removed readily .for inspection or repair.

A particular embodiment has been shown for purposes of illustration only and various changes and modifications may be made therein as will be apparent Lto-aperson skilled in .the art.

'What is claimed is: v

1.;ln a fuel burning device having fuel and air .admission means and a refractory member forming an annular burner throat, said member having an opening communicating with the throat at the periphery thereof, an igniter and flame detector unit for said ,fuel burning device prising a housing having an open small end fitting .said throat opening and side walls flaring outwardly to form a flared chamber, and having a plurality of elongated chambers therein converging axially toward said first chamberand in axial li nment with said open small end of said housing, an ignition burner carried in one of said elongated chambers and disposed to fire through said open small end, a flame detector element mounted in said housing in cooperating relationship with said ignition burner to be-responsive to a flame therefrom, and asecond flame detector element carried by said housing and disposed in axial alignment with another of said elongated chambers and within the range of influence of a flame from said fuel burning device in said burner throat.

2. In a fuel burning device having fuel and air admission means and a refractory member forming an annular burner throat, said member having an opening communicating with the throat at the periphery thereof, an igniter and flame detector unit for said fuel burning device com- .prising a housing having an open small end fitting in said throat opening and side walls flaring outwardly to form a. flared chamber, and having a pluralityof elongated chambers therein converging axially toward said flrst chamber and in .axial alignment with said open small end in said housing, a pair of ignition burners carried respectively in a pair of said elongated chambers and disposed to flre through said open small end, a pair of flame detector elements mounted in said housing in cooperating relationship with the respective ignition burners to be responsive to a flame therefrom, and a third flame detector element carried by said housing and disposed in axial alignment with another of said elongated chambers and within the range of influence of a flamefrom said fuel burner in said burner throat.

3. A device, as set forth in claim 1, in which said first flame detector element includes a flame detector rod mounted in said housing and extending into the path of the ignition burner flame, and said last flame detector element comprises a flame detector rod extending through said other chamber and through said opening into the path of the flame from said fuel burner.

EDWARD R. CLARK.

REFERENCES CITED The following references are of record in the 

